Liquid level control switch



Oct. 21, 1958 E. A. KATHE LIQUID LEVEL CONTROL SWITCH Filed Feb. 1, 1956 1 1T 107 T t 7| 7 a A 4 .4 MM Z w T/ .4 d m mm zch/ INVENTOR.

ggijhvumzd Kai/fie fi0$efdw -e ATTORNEYS llnited States 2,857,492 LIQUID LEVEL CONTROL swrrcn Edmund A. Kathe, Columbus, Shin Application February 1, 1956, Serial No. 562,823

9 Claims. (Cl. 200-84) This invention relates broadly to control devices for maintaining the required level of contained liquids and more particularly to an improved'electric liquid level control Switch.

The purpose'of liquid level control switches is of course well-known; In common, they are constructed with an element positioned to float on the level of a tank-contained liquid and with the actual switch controlling elements physically separated therefrom but operatively associated therewith. Likewise when such devices are installed on the wall of a tank or other container, it is not uncommonpractice to mount the float element substan tially within the tank or, more especially, construct the sameso'that once the device is installed, its functioning parts are only accessible by complete removal for repair or replacement.

The liquid'level control device of this invention differs from those heretofore provided in that it includes a freely rockable member that has no fixed pivot to support or restrain its motion. This member is therefore substantially unconfined and in no wise dependent upon the commonly recognized pintles, levers or the like for its proper functioning.

As will be more specifically disclosed hereinafter, the embodiments of this member may merely comprise a shaft havingat its one end a suitable float bulb and at its opposite'end a block of magnetized material. The block is located in a chamber communicating with the interior of a tank and is attached to the wall of the chamber by reason of its magnetic attraction. Upon fluctuation of the level of the liquid inthe' tank, movements of the float bulb will cause the magnetic block to freely rock or tilt and by so tilting activate a similarly magnetized but physically separated switch member to move the same into either of its circuit controlling positions.

The principal object of this invention therefore resides in'the provision of an improved electric switch for controlling the level of liquids wherein the circuit control members are influenced by a freely rockable magnetic element.

Another object of the invention is to provide an improved'control switch of the above character in which the magnetic actuating element is located in a chambered area whereinthe element responds to fluctuations in the level of the liquid by tilting to produce motion of the switch parts between a circuit open position and a circuit closed position.

Another object of the invention is to provide an improved control' switch having a magnetized element located in a chamber and with a liquid-level influenced bulb connected thereto, said magnetized element being adapted to attract a similar magnetized member though physically sealed therefrom and thereby produce the opening and closing of an electric circuit through the switch.

A further object of the invention is to provide an improved control switch embodying a mercury capsule switch adapted to be bodily rocked between a circuit open position and a circuit closed position, and a magnetic 2,857,492 Patented Oct. 21, 1958 member associated with the capsule'switch and actuated upon rocking movement of a magnetic actuating element to move said capsule switch between its open circuit and closed circuit positions.

Other objects and advantages of the invention will become more apparent during the course of the following description, when read in connection with the accompanying drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the same:

Fig. 1 is a side elevational view of a liquid level switch constructed in accordance with this invention and mounted in an installed position;

Fig. 2 is a vertical sectional view of the switch;

Fig. 3 is a transverse sectional view taken substantially on line 33 of Fig. 2; and I Fig. 4 is a detail sectional view taken substantially on line 4-4 of Fig. 2.

Switch constructions embodying the 'novel features of this invention may be employed in a variety of installations wherein substantial permanency and continuity of satisfactory operation are required. Such a construction eliminates the use of or dependency for continued operation, upon such conventionally known devices as diaphragnis, bellows, springs and leaf-spring elements. Likewise, as herein set forth, the use of buoyant members carried by fixed pivots are eliminated to the end that little or no wear is incurred by the switch actuating parts which are not accessible after installation without disassembly. Thus, a switch control constructed in accordance with this invention can be utilized for the purpose of controlling the liquid level in steam-boilers, water tanks, sump pumps, or to control operations involving a low-water level cut-01f.

With reference now to the drawing, there is shown in Fig. 1 a control switch of this invention-designated in its entirety by the numeral 10. As one example of its utility, the control switch 10 is mounted on the wall 11 of a tank or container 12 containing a supply of a liquid, the level of which is indicated by the numeral 13.

Buoyantly positioned in the liquid and substantially floating in or at the level 13 thereof is a float bulb'14 which constitutes one end of a switch actuating member 15. More particularly, the switch actuating member 15 comprises a shaft 16 having the hermetically-sealed bulb 14 at one end thereof and a cylindrical block 17 at its opposite end which is positioned within an axially disposed chambered area 18 of the body 19 of switch 10'. The block 17 is of a paramagnetic material, such as soft iron or steel, and operates essentially as the actuator element for the circuit controlling switch elements.

The body 19 includes a hollow metallic housing 20 in which the chamber 18 is formed and which has its inner end open to the interior'of the container 12. Carried by the housing 20 and depending therefrom is a casing 23 within which the switch elements are located. The metallic housing 20 has a threaded shank 22 which passes through a hole in the wall 11 of container and is secured in place by means of suitable packing washers 23 and nut 24. The housing 20 isnon-magnetic.

The casing 2i, as shown in Fig. 3, may be formed of a substantially L-shaped panel ZSfixedly secured to the housing 20 and having a vertically disposed wall 26 and a horizontally disposed base 27. Preferably, the casing 21 is closed by a U-shaped cover 28, the associated edges of the panel 25 and cover 28 being stepped to substantially enclose the switchelements. A block of insulation 29, such as {Bakelite or like plastic material, is fixedly mounted in the corner formed by the Wall 26 and base 27 and is provided with embedded threaded sleeves 30 whereby the block can be secured to the panel 25 by means of screws 31. Similar screws 3 32 may also be employed to secure the cover 28. Also embedded in the block 29 are threaded sleeves 33, in spaced relation, which receive connector screws 34 and 3 'for Completing an electric circuit for the switch.

The particular type of switch 36 herein employed is of the so-called mercury capsule-type which includes a tubular glass body 37 containing a bead or quantity of mercury 38 and suitably spaced contact points 39 and 40, said contact points being adapted to complete an electric circuit between wires 41 and 42 when electrical connection is established therebetween by the mercury. The wires 41 and 42 are conventionally secured in the cap-end of the switch body 37 and at their opposite ends are attached to the connector screws 34 and 35. In the well-known manner, the switch is adapted to be tilted to displace the head of mercury 33 between the ends thereof and alternately be angularly positioned to direct the said bead against the contact points 39 and 40.

For this purpose, the body 37 of the switch is carried by a pair of spring clips 43 on the under-side of a metallic support member or bar 44. The support bar 44 is pivotally supported by means of a pin 45 on journal bars 46 that are fixedly attached to the housing 20. The bar 44 is preferably of a magnetically permeable material in order that it will respond in swinging movement to the attraction of a magnetic force directed to- Ward one or the other of its ends. In being controllably swung, under the influence of a substantially external magnetic force, the bar is adapted to tilt the switch 36 and thus open and close a circuit therethrough.

As will be clearly seen, the support bar 44 is located in relatively close proximity to the wall of the housing 20 and since the block 17 of actuating member is in the nature of a permanent magnet, its opposite ends will attract the corresponding ends of bar 44 to swing the same as the block is rocked in response to-the position of the bulb 14 floating on the liquid.

More particularly, the block 17 is equipped with a centrally disposed annular flange or rib 47 which serves as a fulcrum point for rockably supporting the block on the wall surface 48 of chamber 18 and by means of which there will be a positive rocking action of the block at either of its ends. If desired, the annular flange 47 can be increased or reduced in diameter which will vary the amount of angular disposition of the block 17 required to rock from either of its positions of magnetic attraction.

Adjacent the open end of the threaded shank 22 of housing there is formed an annular groove 49 in the wall of the chamber 18 in which is received a locking ring 50. As best seen in Fig. 4, the circular body portion of ring 50 is not continuous but is provided with inwardly directed legs 51 that are arranged in parallel and spaced sufiiciently apart to freely receive the shaft 16 therebetween. The legs 51 however will prevent passage of the block 17 outwardly from the chamber 18; otherwise there is no restriction to bodily rocking movement of the shaft 16 of switch actuating member 15.

The actuating member 15 is thus adapted to rock in generally vertical directions as it is affected by the level of the liquid in container 12 and as the bulb 14 floats thereupon. As the member 15 is caused to rock, the block 17 will be tilted on the flange 47 so that either the end a or the end b will be brought into contact with the'surface 48 of the chamber. Since the block 17 is in the nature of a permanent magnet, the alternate engagement of its ends with the wall of housing 20 will transmit magnetic attraction and cause the support bar 44 to pivot on the journal bars 46.

Thus, when the level of the liquid is lowered, the bulb 14 of actuating member 15 will drop downwardly and will cause the magnetic block 17 to rock on the annular flange 47 thereof until it assumes the broken line position in Fig. 2. This movement will attract the magnetic bar 44 and cause it to swing from the full-line position c to 4 the broken line position :1 (Fig. 2) thereby tilting the switch 36 so that the mercury 38 flows into engagement with the contact points 39 and 40, which action will complete a circuit between the wires 41 and 42. For the purpose of extending this circuit through suitable service lines to a pump, motor or the like, wires 52 and 53 thereof are attached to wires 39 and 40 at screws -34 and 35. The service wires 52 and 53 are inserted into the case 21 of the switch throughanoutlet54provided in the base .27.

Upon reztcration of the liquid within the container to the level indicated at '13, the bulb 14 will be carried upwardly to rock the member 15 in the opposite direction until the magnetic block 17 is back to its original position. This will produce a stronger magnetic force at the end a of said block which will attract the bar 44 causing it to move from its broken line position d to full line position 0 thereby breaking the contact between wires 41 and 42 and opening the switch. It will thus be apparent that the switch actuator member 15 is adapted to be free- 13 and rockably positioned relative to the circuit controlling parts or" the switch by magnetic attraction and that it will rock with the descent and/ or rise of the liquid level in the tank with substantial freedom of movement.

If it is desired to employ the switch 10 to sequentially close one circuit while opening a second circuit, a suitably modified mercury switch may be employed. Also provision is herein made for the attachment of a third service wire by a screw 55 threadably located in the block 29.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred embodiment of the same, but that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

I claim:

1. A switch device, comprising a housing having a chamber therein, magnetic control means mounted exteriorly of said housing, magnetic actuating means positioned within said chamber for moving said magnetic control means, means connected to said magnetic actuating means for moving the same, and means operably connected to said magnetic control means to open and close an electrical circuit upon movement thereof, said magnetic actuating means being rockably mounted in said chamber such that the magnetic poles thereof are opposite unlike poles of the magnetic control means mounted exteriorly of the chamber.

2. A switch device, comprising a housing having a chamber therein, magnetic control means mounted exteriorly of said housing, magnetic actuating means p'ositioned within said chamber for moving said magnetic control means, means connected to said magnetic actuating means for moving the same, and means operably connected to said magnetic control means to open and close an electrical circuit upon movement thereof, said magnetic actuating means comprising a member of magnetic material freely supported within said chamber for rocking movement relative thereto.

3. A switch device as claimed in claim 2, in which the magnetic member comprises a block rockable about a fulcrum point located intermediate its ends.

4. A switch device as claimed in claim 2, in which a' magnetic member, and a switch carried by said magnetic bar and movable therewith to open and close an electrical circuit when said bar is actuated by said magnetic member.

6. A switch device, comprising in combination, a tank for containing liquid, a housing mounted on the tank and having a chamber therein communicating with said tank, actuating means comprising a member of magnetic material located within the chamber, fulcrum means intermediate the ends of said magnetic member to rockably support the same upon the wall of the chamber, means within said tank connected to said magnetic member for rocking the same about its fulcrum according to the level of a liquid within the tank, magnetic control means mounted exteriorly of said housing in opposed relation to said magnetic member and actuated thereby, and circuit controlling means operably connected to said magnetic control means and movable therewith to open and close an electrical circuit.

7. A switch device as claimed in claim 6, including means carried by said housing for preventing accidental displacement of the magnetic member from said chamber.

8. A switch device, comprising in combination, a tank for containing liquid, a housing mounted on the tank and having a chamber therein communicating with said tank, an actuating member including an annular block of magnetic material freely located within the chamber, an annular flange on said block intermediate its ends adapted to support the same for rocking movement upon the wall of the chamber, a float member connected to said block to move the same according to the level of liquid in said tank, a mercury switch located exteriorly of the said housing, and magnetic means for moving the switch between an open circuit position and. a closed circuit position in response to movements of said magnetic block.

9. A switch device, comprising in combination, a tank for containing liquid, a housing mounted on the tank and having a chamber therein communicating with said tank, an actuating member having an annular block of magnetic material located within the chamber, an annular flange on said block intermediate the ends thereof adapted to freely support the same for rocking movement, a magnetic support member pivotally carried exteriorly of the housing in opposed relation to said magnetic block, and means carried by said magnetic support member to open and close an electric circuit upon magnetic attraction of said magnetic support member by said magnetic block upon rocking of the latter.

References Cited in the file of this patent UNITED STATES PATENTS Binford Mar. 5, 1957 

